Georgios Keliris
Main Focus
Neural circuits subserving visual perception
Vision is the sense that dominates the way we perceive our external world. Each moment, the visual system is challenged with processing immense amounts of information entering the eyes with only a small fraction reaching our awareness. What are the neural circuits responsible for the selection which leads to our visual experience? Finding the neural correlates of perception is not an easy endeavor. The difficulty stems from the fact that a perceptual event is almost always coupled with sensory stimulus changes, setting unclear whether the neural responses are related to perception or simply a response of the sensory processing mechanisms. To this end, multi-stable stimuli can provide unique insights into perceptual selection mechanisms, as changes in perception are decoupled from changes in the stimulus which remains unchanged. My research focuses in finding the neural underpinnings of visual perception by using high density multi-electrode recordings and state of the art fMRI in human and non-human primates.
Selected Publications
A new method for estimating population receptive field topography in visual cortex.
S. Lee, A. Papanikolaou, N.K. Logothetis, S.M. Smirnakis & G.A. Keliris, NeuroImage, 81:144-157, 2013
Visual Cortex organization in a macaque monkey with macular degeneration
Y.Shao*, G.A. Keliris*, A. Papanikolaou, M.D. Fischer, D. Zobor, H.Jaegle, N.K. Logothetis, & S.M. Smirnakis, Eur J Neurosci, Aug 2013
Introduction to research topic binocular rivalry: a gateway to studying consciousness.
A. Maier, T.I. Panagiotaropoulos, N. Tsuchiya & G.A. Keliris, Frontiers in Human Neuroscience, 6(263):1-3, 2012
Detailed functional and structural characterization of a macular lesion in a rhesus macaque.
M.D. Fischer, D. Zobor, G.A. Keliris, Y Shao , M.W. Seeliger, S. Haverkamp, H. Jägle, N.K. Logothetis & S.M. Smirnakis, Documenta Ophthalmologica, 125(3):179-194, 2012
The role of the primary visual cortex in perceptual suppression of salient visual stimuli.
G.A. Keliris, N.K. Logothetis & A.S. Tolias, Journal of Neuroscience, 30(37):12353-65, 2010
Decorrelated neuronal firing in cortical microcircuits.
A.S. Ecker, P. Berens, G.A. Keliris, M. Bethge, N.K. Logothetis & A.S. Tolias, Science, 327(5965):584-7, 2010
Feature selectivity of the gamma-band of the local field potential in primate primary visual cortex.
P. Berens, G.A. Keliris, A.S. Ecker, N.K. Logothetis & A.S. Tolias, Frontiers in Neuroscience, 2(2):199-207, 2008
Robust controlled functional MRI in alert monkeys at high magnetic field: effects of jaw and body movements
G.A. Keliris, A. Shmuel, S.-P. Ku, J. Pfeuffer, A. Oeltermann, S. Thomas & N.K. Logothetis, NeuroImage, 36(3):550-570, 2007
A binocular rivalry study of motion perception in the human brain.
K. Moutoussis, G.A. Keliris, Z. Kourtzi & N.K. Logothetis, Vision Research, 45(17):2231-43, 2005
Neurons in macaque area V4 acquire directional tuning after adaptation to motion stimuli.
A.S. Tolias, G.A. Keliris, S.M. Smirnakis & N.K. Logothetis, Nature Neuroscience, 8(5):591-593, 2005
Curriculum Vitae
Curriculum Vitae
Georgios A. Keliris, Ph.D.
E-mail: georgios.keliris@tuebingen.mpg.de
Education
Ph.D. Neural and Behavioral Sciences, 2008
Max-Planck Institute for Biological Cybernetics
(Laboratory of Prof. Dr. Nikos K. Logothetis)
International Max Planck Research School,
University of Tübingen, Germany
M.Sc. Neural and Behavioral Sciences, 2003
International Max Planck Research School,
University of Tübingen, Germany
B.Sc. Physics, 2000
University of Cyprus
Thesis
Nov 2007 Ph.D. Thesis: Investigating the Neural Correlates of Visual Perception Supervisors: Prof. Dr. Nikos K. Logothetis, Dr. Andreas S. Tolias
Feb 2003 M.Sc. Thesis: Evaluation of Single Unit Isolation: Tetrode Recordings in Awake Behaving Macaques Supervisor: Dr. Andreas S. Tolias
June 2000 B.Sc. Thesis: Strategies for the search of the HIGGS boson in the CMS experiment. Fission channel: Higgs to two photons. (in Greek) Supervisor: Prof. Dr. Panos Razis
Awards and Distinctions
June 1998 Early Academic Performance Award for the best performance in the core subjects of the Degree in Physics, University of Cyprus
June 2000 First Award of the Faculty of Physics, University of Cyprus, for finishing 1st in the ranking of the Faculty
Jan 2001 Oct 2001 Stipendium by the Max-Planck Gesellschaft
Oct 2001 Oct 2002 Scholarship by the DAAD for further academic study and training
2002 2005 Scholarship by the Max-Planck Gesellschaft for Doctoral studies
2008 2009 Post-doctoral fellowship scholarship by the Max-Planck Gesellschaft
June 2009 Nov 2012 Post-doctoral fellowship from the ERC FP7 (Plasticise project)
May 2010 July 2015 Principal investigator in a project of the Bernstein center for computational neuroscience (BCCN) Tuebingen (funds 2 Ph.D. student plus additional travel expenses and publication fees)
Research Internships
Feb 2001 Sep 2001 Program developing for optimal visualization of the brain data collected by MEG and fMRI
MEG Center, University of Tübingen
Dr. Christoph Braun, Dr. Nikolaus Weiskopf
Sep 2001 Feb 2002 Human fMRI studies of the perceptual filling-in
Max Planck Institute for Biological Cybernetics
Dr. Stelios Smirnakis, Dr. Zoe Kourtzi
Feb 2002 Aug 2002 Connectivity of networks derived from firing properties of simulated neurons
Gatsby Computational Neuroscience Unit, University College London
Prof. Dr. Peter Dayan
Aug 2002 Feb 2003 Neural basis of decisions: fMRI studies in macaques
Max Planck Institute for Biological Cybernetics
Dr. Andreas S. Tolias
June 2012 Aug 2012 The role of attention in center-surround interactions in the visual cortex
Brain Science Institute, RIKEN, Japan
Prof. Dr. Justin L. Gardner
Publications
Shao Y*, Keliris GA*, Papanikolaou A, Fischer MD, Zobor D, Jaegle, H, Logothetis NK, Smirnakis SM (2013)
Visual cortex organization in a macaque monkey with macular degeneration
Eur J Neurosci 2013
Lee S, Papanikolaou A, Logothetis NK, Smirnakis SM, Keliris GA (2013)
A new method for estimating population receptive field topography in visual cortex
NeuroImage 2013; 81:144-157
Maier A, Panagiotaropoulos TI, Tsuchiya N, Keliris GA (2012)
Introduction to research topic - Binocular rivalry: a gateway to studying consciousness
Front Hum Neurosci 2012; 6(263):1-3
Fischer DM, Zobor D, Keliris GA, Shao Y, Seeliger MW, Haverkamp S, Jägle H, Logothetis NK, Smirnakis SM (2012)
Detailed functional and structural characterization of a macular lesion in a rhesus macaque.
Doc Ophthalmol. 125(3):179-194
Stoewer S, Goense J, Keliris GA, Bartels A, Logothetis NK, Duncan J, Sigala N (2012)
An analysis approach for high-field fMRI data from awake non-human primates.
PLoS One. 2012; 7(1)
Stoewer S, Goense J, Keliris GA, Bartels A, Logothetis NK, Duncan J, Sigala N (2011)
Realignment strategies for awake-monkey fMRI data.
Magn Reson Imaging. 2011; 29(10):1390-400
Keliris GA, Logothetis NK, Tolias AS (2010)
The role of the primary visual cortex in perceptual suppression of salient visual stimuli.
J Neurosci. 2010; 30(37):12353-65
Ecker AS, Berens P, Keliris GA, Bethge M, Logothetis NK, Tolias AS (2010)
Decorrelated neuronal firing in cortical microcircuits.
Science. 2010; 327(5965):584-7
Berens P, Keliris GA, Ecker AS, Logothetis NK, Tolias AS (2008)
Feature selectivity of the gamma-band of the local field potential in primate primary visual cortex.
Front Neurosci. 2008; 2(2):199-207
Berens P, Keliris GA, Ecker AS, Logothetis NK, Tolias AS (2008)
Comparing the feature selectivity of the gamma-band of the local field potential and the underlying spiking activity in primate visual cortex.
Front Syst Neurosci. 2008; 2:2
Tolias AS, Ecker AS, Siapas AG, Hoenselaar A, Keliris GA, Logothetis NK (2007)
Recording chronically from the same neurons in awake, behaving primates
J Neurophysiol. 2007; 98(6):3780-90
Keliris GA, Shmuel A, Ku SP, Pfeuffer J, Oeltermann A, Steudel T, Logothetis NK (2007)
Robust controlled functional MRI in alert monkeys at high magnetic field: effects of jaw and body movements. Neuroimage. 2007; 36(3):550-70
Pfeuffer J, Shmuel A, Keliris GA, Steudel T, Merkle H, Logothetis NK (2007)
Functional MR imaging in the awake monkey: effects of motion on dynamic off-resonance and processing strategies.
Magn Reson Imaging. 2007; 25(6):869-82
Tolias AS, Keliris GA, Smirnakis SM, Logothetis NK (2005)
Reply to "Motion processin in macaque V4"
Nat Neurosci. 2005; 8(9):1125
Moutoussis K, Keliris GA, Kourtzi Z, Logothetis NK (2005)
A binocular rivalry study of motion perception in the human brain.
Vision Res. 2005; 45(17):2231-43
Tolias AS, Keliris GA, Smirnakis SM, Logothetis NK (2005)
Neurons in macaque area V4 acquire directional tuning after adaptation to motion stimuli.
Nat Neurosci. 2005; 8(5):591-3
Book Chapters
Panagiotaropoulos TI, Logothetis NK, Keliris, GA (in press)
Neural approaches to perceptual organization.
The Handbook of Computational Perceptual Organization (Eds. Gepshtein-Maloney)
Editorials
Special Research Topic in Frontiers in Human Neuroscience
(co-hosted with A. Maier , T.I. Panagiotaropoulos, N. Tsuchiya)
Student supervision
May 2007 Feb 2009
Masters thesis: Correlates of perception in primate primary visual cortex) now Ph.D. student with Prof. Dr Anthony Holtmaat at University of Geneva
Aug 2009 Oct 2009 Kristin Herper
Lab rotation: Binocular receptive field mapping after adaptation
Feb 2011 Apr 2011 Pooja Viswanathan
Lab rotation: Spike-LFP phase locking across frequency bands under different task conditions now Ph.D. student at University of Tuebingen.
Nov 2011 Aug 2012 J Kausik Lakshminarasimhan
Masters thesis: Neuronal gamma-band synchronization in macaque area V1 follows changes in firing rate during monocular stimulation. now Ph.D. student at Baylor College of Medicine, Houston, TX
Jun 2009 to date (Ph.D. student ) - co-supervised with Prof. Stelios Smirnakis (Baylor)
Project title: Visual cortical plasticity after V1 lesion and retina degeneration in macaque monkeys
Sep 2009 to date (Ph.D. student)
Project title: The role of parietal visual cortex in perceptual transitions during bistable perception
Nov 2009 to date (Ph.D. student) - co-supervised with Prof. Smirnakis (Baylor)
Project title: Visual cortex reorganization in human subjects with cortical lesions
Feb 2010 to date (Ph.D. student) funded by DAAD
Project title: Effects of attention on neural processing in the striate cortex on non-human primates: a simultaneous electrophysiology fMRI study
Apr 2011 to date (Ph.D. Student) funded by
Project title: Neuronal population activity underlying multi-stable motion perception